1. Field of the Inventive Concept
The present inventive concept relates to a nonvolatile memory device and a method for sensing the same.
2. Background
A nonvolatile memory device (resistive memory device) using a resistance material includes a phase change random access memory (PRAM) or a phase change memory (PCM), a resistive RAM (ReRAM), a magnetic RAM (MRAM), and the like. A dynamic RAM (DRAM) or a flash memory stores data using charges, whereas a nonvolatile memory device using the resistance material stores data using the state change of a phase change material such as a chalcogenide alloy (in the case of a PRAM), a resistance change of a variable resistance material (in the case of an RRAM), a resistance change of a magnetic tunnel junction (MTJ) according to a magnetization state of a ferromagnetic material (in the case of an MRAM), and the like.
Here, a phase change memory device will be described as an example. A state of a phase change material is changed to a crystal state or an amorphous state while the phase change material is cooled after being heated. The phase change material in a crystal state has low resistance, and the phase change material in an amorphous state has high resistance. Accordingly, the crystal state may be defined as set data or 0 data, and the amorphous state may be defined as reset data or 1 data.